Same way most of use found our way here, "the internet". I don't believe it's the act of introducing others to the forum that attracts scammers. Instead, they find their way here through the internet. They aren't just on BitcoinTalk, but also on all social media platforms. Most ordinary people who haven't come across Bitcoin aren't interested in it or cryptocurrency. Meanwhile, those interested but not on this platform likely lack information about it.

Many people are aware of Bitcoin but don't see the need to create an account. That's why you often see new accounts asking important questions and then disappearing. So to answer your question it's unlikely that those referred here turn out to be scammers. although some may be spammers joining for signature campaigns. However, scammers manage to infiltrate every platform.